Learning and Memory

Question 1

What are the two types of memory?

Answer 1

Declarative - memories that can be brought to conscious awareness, i.e. facts

Procedural - not directly available to conscious awareness, i.e. skills, habits

Question 2

What is immediate memory?

Answer 2

Sum of all sensory input currently being processed at the cortical level

Very large capacity

Question 3

What is short-term memory?

Answer 3

Conscious attention allows information to enter short-term memory

Small capacity

Question 4

What is long-term memory?

Answer 4

Resistant to forgetting, very large capacity

Retained through a process called consolidation

Question 5

What is amnesia?

Answer 5

Declarative memory impairment

Question 6

What is retrograde amnesia?

Answer 6

Loss of memories which were already formed

Results from damage to areas where long-term memories are stored

Question 7

What is anterograde amnesia?

Answer 7

Inability to form new memories

Question 8

What structures are responsible for procedural memory?

Answer 8

Motor system structures

Cerebellum, basal ganglia, premotor cortex

Question 9

What structures are responsible for delcarative memory?

Answer 9

Cortical areas involved in cognitive and perception

Medial temporal lobe of limbic system, Wernicke’s area, etc.

Question 10

What structures are responsible for short-term memory?

Answer 10

More than one structure, thought to be high level sensory/association areas

Information may also be transferred to areas within the prefrontal cortex for storage

Question 11

What structures are responsible for long term memory?

Answer 11

High level sensory/association areas which are responsible for perception of complex stimulus properties

Lesions within these cortical areas produce specific deficits affecting both memory and perception

E..g Prosopagnosia

Question 12

What is consolidation?

Answer 12

Formation of long-term memory through the strengthening of synaptic connections between neurons in multiple cortical areas

Requires the papez circuit

Question 13

What results from bilateral damage to the medial temporal lobe?

Answer 13

Global anterograde amnesia

Damage includes hippocampus, entorhinal cortex, and parahippocampal gyrus

Question 14

What results from bilateral damage to the medial diencephalon?

Answer 14

Global anterograde amnesia

Mammillary bodies, anterior thalamus

Also can be caused by damage to the dorsomedial thalamus

Question 15

What results from unilateral lesions to the medial temporal or medial diencephalon?

Answer 15

Produces antergrade amnesia, but severity is reduced from bilateral lesions, and severity may be mild

Question 16

What process is responsible for synapse strengthening/weakening?

Answer 16

Long-term potentiation

Long-term depression

Question 17

What type of channels are present on the post-synaptic spines of pyramidal neurons?

Answer 17

AMPA and kainate

NMDA

Question 18

How are NMDA receptors dually gated?

Answer 18

They require depolarization and glutamate to open fully

Question 19

What occurs in the post-synaptic membrane when the glutamate synapse is activated by a single presynaptic AP?

Answer 19

AMPA and kainate receptors open, but NMDA receptors are not because there is not enough depolarization

Question 20

What occurs with repetitive use of the synapse?

Answer 20

The EPSPs add up and depolarize the postsynaptic neuron sufficiently to open the NMDA receptors

This allows calcium to flow into the spine and activate calcium dependent enzymes

Question 21

What are two ways the activation of calcium dependent enzymes increases the sensitivity of the postsynaptic neuron to glutamate?

Answer 21

Phosphorylation of AMPA/KA receptors

New AMPA/KA receptors are inserted into the membrane

Question 22

What is the retrograde messenger in LTP and what is its function?

Answer 22

Nitric oxide

Causes enhanced glutamate release from the presynaptic terminal

Question 23

How do long lasting (permanent) changes to synapse strength occur?

Answer 23

Production of new proteins (glutamate receptors, cytoskeletal) initiated by signals of unknown origin

Newly synthesized proteins induce the creation of new synaptic contacts

Question 24

Describe long term depression

Answer 24

Increased postsynaptic calcium stimulation activation of phosphatases that dephosphorylates AMPA/KA receptors and causes their removal from the membrane

Thought to be controlled by a lower level of intracellular calcium than LTP

Question 25

How are multiple cortical areas activated in long-term memory storage?

Answer 25

Neruons that interconnect these areas are strengthened due to memory formation

After the formation of the memory, activation of any one of these areas will now lead to the recall of all aspects of the memory for this person

Question 26

How are declarative memories retrieved?

Answer 26

Initiated by reactivation of one of the cortical areas where an aspect of the memory is stored

Variable - may not reactivate all areas where the memory is stored

Sometimes incorrect